Later, the left banks of several production 389 engines were removed. Even with the extra drag of the deactivated cylinders, the cobbled-up test engine had enough steam to propel the 4,000-plus-pound sedan to a top speed of 92 mph and still give satisfactory gas mileage. In order to prove that the concept was valid, engineers took a production 389-cid Pontiac V-8 engine, put holes in the left bank of pistons, disabled the valve-train for the same cylinders, and reinstalled it in a full-sized Pontiac. See how Pontiac Tempest revolutionized the compact car with its four-cylinder engine on the next page. Its intended benefits to the Tempest will be explained in a bit. Obviously, quite a bit of expense went into the development and manufacture of the flexible driveshaft. The manufacturing process was finished with a rust-inhibiting coating. The shafts were surface ground and magnafluxed for imperfections before shot-peening and final straightening procedures. Since the shafts were transmitting engine torque that was not multiplied by the transmission, they were understressed and could easily afford to be as small in diameter as they were compared to a conventional driveshaft. Tempests with manual transmissions featured a shaft diameter of '75 inches, while automatics received a '65-inch-diameter unit. The shaft was actually a forged-steel torsion bar, which featured high nickel, chrome, and molybdenum content. It soon earned the nickname "rope drive," which was not an accurate depiction of the driveshaft. The design was truly revolutionary, though not always understood by the public. Buick and Oldsmobile, however, were not planning on using any such exotica on their small cars, preferring to stick with conventional drivetrain layouts. The smaller size also suggested an inherent sportiness and DeLorean believed he could meet these objectives, as well as achieve the ideal 50/50 weight distribution by using a flat floor, a rear-mounted transaxle, and, of all things, a flexible driveshaft. In addition to offering lower purchase and running costs, the new design needed to possess a "big-car" ride and offer comfortable seating for six adults. The solutions that DeLorean and his team implemented demonstrated their expertise at working creatively within a clearly defined set of boundaries.ĭeLorean wanted a car that was more than just a compact. In order to come in at a competitive price, the compact Pontiac would have to make as much use of existing technology and production facilities as possible. DeLorean, was anxious to put his stamp on the "Wide Track" portion of the project. Pontiac's director of advanced engineering, John Z. DeLorean helped shape the Pontiac Tempest. Though Pontiac knew what they did not want to do, they needed to pick a direction for their new compact car. Therefore, how do I justify the extra $500 to $1,000 added to the price to sell it with a Pontiac nameplate?'" How do I make it different? There is no grille to be restyled and the engine can't be exchanged for a Pontiac powerplant. DeMauro, then-technical editor for High Performance Pontiac magazine, Knudsen explained why: "'First, if a dealer tells people that this is a new, more-advanced design, then how will the salesman justify the traditional drivetrain layouts found in Pontiac's other lines? Second, the Corvair is a rear-engine, air-cooled car. "Bunkie" Knudsen, did not want a tarted-up Corvair (to be named Polaris) as a Pontiac. Pontiac's general manager at the time, Semon E. Pontiac, being next up the ladder from Chevrolet in the GM lineup, was the most logical choice, but Oldsmobile and Buick were under consideration for their own versions as well. Perhaps the strongest motivation for its development was the Corvair, or more specifically, Pontiac's desire to not get a badge-engineered version of it.Ĭorporate management was looking to extend the platform's reach into other divisions, increasing sales volume to offset the development costs of the unique rear-engined compact. The story behind the development of the Tempest is one of divisional defiance and cost-conscious innovation. Without a doubt, the Tempest featured the most unusual drivetrain of the trio, one of the most technologically advanced systems offered in an American car up to that time. Mechanically, though, there were significant differences between them. The fraternal triplets were based on a 112-inch-wheelbase platform featuring unitized construction and the same basic Fisher body. In between these two Chevrolets, in terms of chronology and technology, were the "B-O-P" compacts: Buick Special, Oldsmobile F-85, and Pontiac Tempest. General Motors offered the most diverse line of compact cars, from the radical, rear-engined 1960 Corvair to the completely conventional Chevy II that debuted two years later.
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